How to draw a vertical line at certain x values on a plot

I am creating a timecourse of some EEG data and I would like to create a vertical line that goes from the bottom to the top of the plot to indicate when the cluster ends and starts.

Answer 1

[Tommy]

hold on;
plot([x x], ylim)

Or better yet, in case you have multiple sets of axes:

% if ax is the set of axes you are plotting to
hold(ax, 'on');
plot(ax, [x x], ylim(ax))

[Star Strider]

Another option is xline (R2018b and later releases).

[Vishnu Pendri]

thanks!